Special Poster Session Biofabrication
Evaluation of inkjet printing for ADA-PEG bioinks
Emine Karakaya, Andreas Frank, Leo Forster, Jörg Teßmar,
Hans-Werner Schmidt, Aldo Boccaccini & Rainer Detsch
Inkjet printing of living cells is an emerging additive manufacturing (AM) technology for different life science approaches, for example regenerative medicine, cancer research, lab on a chip and synthetic biology. It is well known that piezo inkjet technology is successfully applied to water-based bioink systems . For this technology, sodium alginate is one favorable bioink because of its high biocompatibility. Additionally, synthetic polymers like poly(ethylene glycol) (PEG) are promising candidates to further tune the properties to improve the final properties of the bioink.
The inkjet printing applied in this study is based on an electromagnetic valve and is able to handle higher viscosities compared to the piezo technology. Regarding the bioinks, we developed a set of hybrid materials consisting of alginate and star-shaped PEGs (star-PEGs) that can be independently varied in physical characteristics e.g. molecular weight and biomolecular functionalization. Alginate polymers were oxidized to alginate dialdehyde (ADA)  to provide reaction sites for modified PEG compounds (e.g. amino-PEG). In order to characterize the PEG-modified bioinks and to monitor the success of the reaction between ADA and Amino-PEGs, fourier-transform infrared spectroscopy and ultraviolet–visible spectroscopy were used, respectively. Viscosity and gelation were investigated using rheology measurements. Finally, we embedded NIH3T3-cells in ADA-PEG hydrogels in order to use this combination as a suitable bioink for drop-on-demand approaches. The cell behavior were analysed after 24 h of incubation.
In summary, it has been proven that the inkjet printing process of cells in different ADA-PEG hydrogel formulations is a promising approach. The applied electromagnetic inkjet printing is shown to be completely programmable, accurate and the resolution of the device allowed printing of various patterns with bioinks and vital cells.
 Detsch R, Blob S, Zehnder T, Boccaccini AR. Evaluation of cell inkjet printing technique for biofabrication. BioNanoMaterials. 2016
 Sarker B, Papageorgiou DG, Silva R, Zehnder T, Gul-E-Noor F, Bertmer M, et al. Fabrication of alginate-gelatin crosslinked hydrogel microcapsules and evaluation of the microstructure and physico-chemical properties. J Mater Chem B. 2014